US politician Gabrielle Giffords has been released from hospital five months after she was shot in the head at point-blank range in an attack that shocked the US.

A few days after the first photos of her since the attack were published, doctors said 'her cognitive abilities and physical strength have improved to the point where she no longer needs to remain a patient in the hospital'.

'Congresswoman Giffords has shown clear, continuous improvement from the moment she arrived five months ago,' said Dr Gerard Francisco, the hospital's chief medical officer, in a statement.

He added: 'We are very excited that she has reached the next phase of her rehabilitation and can begin outpatient treatment.

'We have no doubt that she will continue to make significant strides in her recovery.'

Six people, including a federal judge and a nine-year-old girl, were killed and 12 others wounded in the shooting on 8 January.

In March, the alleged gunman, Jared Loughner, was declared mentally unfit to stand trial.

Experts found the 22-year-old to be schizophrenic and unable to help in his own defence or understand court proceedings.

Photos of a smiling Ms Giffords were posted on her Facebook page last weekend.